1. Field of the Invention
The present invention relates to a vehicle collision damage reduction system, and more specifically, it relates to a system for minimizing injury to the occupant suffered in a vehicle collision. This system works to detect an unavoidable collision during vehicle travel just prior to the collision and to deform the vehicle""s structure in the collision, thus absorbing enough collision energy to ensure adequate safety space for the occupant and to enable occupant restraint protection devices to operate effectively.
2. Description of the Related Art
Various vehicle structures and occupant protective devices have been previously developed to attempt to reduce injury to occupants in a vehicle collision. The features of and problems in conventional vehicle structures and occupant protective restraining devices generally will be described below.
Vehicle Structure for Damage Reduction in Collision
To achieve reduction in occupant injury in a collision, it is first important that a safety space for an occupant be secured in the vehicle structure and that the impact applied to the occupant be reduced in a vehicle collision and in a secondary collision.
Vehicle Structure
A conventional vehicle structure of a passenger vehicle can be designed keeping in mind several assumptions regarding various collision conditions for occupant safety. In general, a crushable zone is provided in the front and rear of a vehicle structure so as to absorb impact reliably in a collision while the structural rigidity of the cabin portion as a safety space is increased for the safety of the occupants. For example, in a head-on collision, front members such as front cross members, side members, and vehicle frames are designed to be crushed in sequence to receive collision energy and thereby absorb the energy so as to minimize the deformation and rupture of the cabin portion.
However, when the collision speed is higher than the assumed value for designing members of various parts and the vehicle frame, the cabin can be greatly deformed so that an occupant restraint protective device in the cabin might be in danger of being injured and thereby not protecting the occupant properly against the applied collision energy. Also, impact energy absorption by the vehicle might be insufficient, depending on the form of the collision.
Steering Mechanism for Impact Absorption
In certain known steering mechanisms, an impact absorption mechanism may be included which undergoes displacement in the front direction when a predetermined load is applied thereto, Such steering mechanism may be assembled on the assumption that a steering wheel located in front of an occupant might be an element capable of injuring the occupant in a collision, e.g., the occupant""s torso or other areas, when the occupant collides with the steering wheel in the secondary collision following after the initial vehicle collision. A collision xe2x80x9cenergy absorbingxe2x80x9d structure (an xe2x80x9cEAxe2x80x9d structure) also may be assembled in an alignment device of the steering mechanism or within a column shaft so as to attempt to reduce injury.
Since EA load characteristics for this structures are designed at this time to assume that the occupant is of AM 50% (i.e., the standard size of adult male) colliding under a predetermined condition, these assumptions may be not the most suitable for occupants having various physiques and sitting in various states and for various collision states to best attempt to reduce occupant injury. A more variable system is needed.
Occupant Restraint Protective Devices for Reducing Injury in a Collision
As a typical example of an occupant restraint protective device, a seatbelt device, an airbag, and a child seat are known and becoming wide spread. However, they have the following undesirable characteristics:
In a conventional seating position, an occupant is free to assume different seating postures. The occupant even may have an unsuitable posture for securing him safely by a seatbelt or an airbag. For example, the following seating postures are not the best for providing adequate safety to the occupant:
(1) sitting excessively close to the steering wheel
(2) sitting with an excessively inclined seat back
(3) lower seat surface at the front than that at the rear.
It is preferable that the occupants having the posture be corrected to have proper posture and a proper position for being properly restrained.
In a conventional seatbelt take-up device with a pre-tensioner, the pre-tensioner is activated by determining a collision scale from the acceleration and the speed-change rate detected by a crush detecting sensor, etc. When a head-on collision of a vehicle occurs, for example, a difference of relative speed between an occupant and the vehicle occurs in a slight delay period just after the collision because of the inertia force applied to the occupant when the vehicle speed is zero. In order to drive the pre-tensioner of the seatbelt for restraining the occupant moving within such a slight time difference, a large driving force is needed. Therefore, in a conventional pre-tensioner, a strong and heavy driving source large in size is used, so that a miniaturized and lightweight seatbelt take-up device having the pre-tensioner assembled therein is difficult to be achieved.
Child Seat
In a conventional child seat (referred to as a xe2x80x9cCRSxe2x80x9d or xe2x80x9cChild Restraint Seatxe2x80x9d), because an infant is seated thereon in a collision, a restraining effect is changed in accordance with the installing state of the CRS and the reclining state. For example, when the CRS is installed forward-facing in an upright position in a collision, the impact applied to the infant is substantially restrained by buckle and belt portions. In contrast, in a reclining position, it is assumed that part of the restraining load applied to the belt can be relieved by the seat surface because the seat surface is formed to serve as a supporting face relative to the colliding direction.
On the other hand, when a collision occurs with the CRS installed rearward-facing in a reclining position, although an infant is supported by a seat back portion, the infant starts to slide in the collision direction because the inclination angle is small, so that the infant is restrained in the loaded state on a shoulder belt. However, when the CRS is in an upright position, it is assumed that the load is substantially supported by the seat back because of the large angle of inclination.
Improving Damage Reduction in Collision by Using a Collision Predicting Sensor System
To attempt to overcome some of these problems, a collision safety system has been under development in which a collision is unavoidable by determining the distance between the vehicles and the acceleration state by using a non-contact distance sensor using, inter alia, radio waves (millimetric waves), a laser, ultrasonic waves, acoustic sound waves, visible light, or the like. In such a system, for example, an embodiment is considered in that the occupant restraint protective device starts to function just before a collision in accordance with an emergency level which is determined in stages by a collision danger level determining circuit arrangement in the system, which utilizes the above-mentioned non-contact distance sensor as a collision predicting sensor attached to the front end of an own vehicle for detecting a running speed of the own vehicle, a distance and a relative speed to another vehicle or an obstacle (object to be impacted), and so forth. Some of the applicants has developed a technique disclosed in Japanese Unexamined Patent Application Publication No. 9-132113 as a criterion of assessing various danger levels with respect to the severity of the impending collision, which is hereby incorporated herein its entirety. By utilizing such a developed technique, a more advanced damage reduction method from a collision is achieved.
As mentioned above, when a collision is detected just before the collision, the above-mentioned vehicle structure and the occupant restraining and protecting device respectively serve the following functions at a vehicle collision, thereby, injury reduction may be achieved.
Safety Vehicle Structure
When the collision speed is large, the energy absorbing capacity is increased corresponding to the speed. Besides a full-lap collision, even when an offset collision having a lapping rate of 50% or less occurs, the collision energy is efficiently absorbed by only the vehicle part on the collision side. xe2x80x9cLapping ratexe2x80x9d means the amount which a vehicle collides with and overlaps an object or vehicle upon a collision.
Before a secondary collision occurs just after a vehicle collision, the capacity to absorb occupant collision energy is increased. For example, the distance between an occupant (driver) and the steering wheel is increased without sacrificing steering operability, thereby minimizing injury to the torso and/or the head of the occupant against the steering wheel during the collision. In order to reduce damage of occupants having various physiques and seated postures, the EA load characteristics are preferred to be capable of being varied.
Occupant Restraining and Protecting Device: Seat-adjusting Mechanism
When an occupant has an undesirable seating posture, the posture is desired to be properly corrected so that the occupant can be properly restrained and protected by the seatbelt device and the airbag. Thereby, even when an occupant has proper seating posture, the restraining function can be furthermore improved. When the object detecting means such as the collision predicting sensor is used in the correcting operation, sufficient operating time for the device can be secured and the correction can be performed by taking the collision danger level into consideration. In this way, the restraining and protecting means can function in a moderate mode of operation, depending on the situation, without always using a momentary, actuating high-power driving device.
Seatbelt Pre-tensioner
In order to drive the pre-tensioner of the seatbelt so as to restrain an occupant within a short time before the displacement of the occupant just after the collision, high-power driving force is required. However, when the object detecting means such as the collision predicting sensor is used in the correcting operation, sufficient operating time for the device can be secured and the correction can be performed by taking the collision danger level into consideration. In this way, the restraining and protecting means can function in a moderate mode of operation, depending on the situation, without always using a momentary actuating high-power driving device. Therefore, the pre-tensioner device can be miniaturized and also can provide very effective protection that restrains an occupant before the movement.
CRS Reclining Mechanism
When a collision occurs when a CRS is installed to the seat, the various reclining positions of the CRS can be corrected to have desired or optimum posture for minimizing collision injury, so that impact applied to an infant at the collision is dispersed over a more wider area in order to support the infant. When the object detecting means such as the collision predicting sensor is used in the correcting operation, sufficient operating time for the device can be secured and the correction can be performed by taking the collision danger level into consideration. In this way, the restraining and protecting means can function in a moderate mode of operation, without always using a momentary, actuating high-power driving device.
The above-mentioned functions may be achieved by the present invention.
In accordance with a first aspect of the present invention, there is provided a vehicle collision damage reduction system comprising at least one object detecting means for sequentially detecting distance information to an object to be impacted moving relatively, and collision danger level determining means for determining a collision danger level so as to output collision predicting information by sequentially detecting the distance information; collision energy absorbing means in a vehicle structure formed to support part of the vehicle structure in advance for absorbing collision energy applied thereto in a collision; and controlling means for outputting an operational command, before the collision, to the collision energy absorbing means in a vehicle structure on the basis of the collision predicting information obtained from the object detecting means or the collision danger level determining means.
Preferably, the collision energy absorbing means in a vehicle structure is introduced as part of the vehicle structure in advance of an airbag and formed to support part of the vehicle structure. The airbag can be inflated, before a collision, by an operational command from the controlling means and deforming so as to absorb the collision energy applied thereto when the vehicle structure deforms at the collision.
The expansion rate or the energy absorbing amount of the airbag for the vehicle structure may be preferably changed in stages in response to the collision danger level based on the collision predicting information obtained from the collision danger level determining means.
In accordance with a second aspect of the present invention, there is provided a vehicle collision damage reduction system comprising at least one object detecting means for sequentially detecting distance information to an object to be impacted moving relatively, and collision danger level determining means for determining a collision danger level so as to output collision predicting information by sequentially detecting the distance information; collision energy absorbing means for a vehicle occupant for absorbing collision energy applied to an occupant in a secondary collision following a vehicle collision; and controlling means for outputting an operational command, before the collision, to the collision energy absorbing means for a vehicle occupant on the basis of the collision predicting information obtained from the object detecting means or the collision danger level determining means.
The collision energy absorbing means for a vehicle occupant may be preferably steering column shortening means introduced in part of a steering column or a shaft to be shortened in the axial direction, before a collision, by an operational command from the controlling means, so as to increase the distance between the occupant and the steering column or a shaft.
Load characteristics of the collision energy absorbing means for a vehicle occupant introduced in part of a steering column or a shaft may also be preferably changed in stages in response to the collision danger level of the collision predicting information obtained from the collision danger level determining means.
Preferably, a vehicle collision damage reduction system further comprises occupant seating information detecting means for detecting physique and a seating state of an occupant seated in a seat so as to output seating state information to the controlling means, wherein the operational amount of the collision energy absorbing means for a vehicle occupant is established, before a collision, on the basis of the seating state information obtained by the occupant seating information detecting means. The xe2x80x9cseating statexe2x80x9d is defined as the condition how the occupant is seated in a seat, such as how close to the steering wheel, how far the seat back is inclined, etc.
In accordance with a third aspect of the present invention, there is provided a vehicle collision damage reduction system comprising at least one object detecting means for sequentially detecting distance information to an object to be impacted moving relatively and collision danger level determining means for determining a collision danger level so as to output collision predicting information by sequentially detecting the distance information; a seat adjusting mechanism capable of adjusting seat sliding, reclining, and seat height of a seat independently or simultaneously; controlling means for outputting an operational command of a predetermined seat adjustment amount to the seat adjusting mechanism on the basis of the collision predicting information obtained from the object detecting means or the collision danger level determining means; and occupant seating information detecting means for detecting physique and a seating state of an occupant seated in a seat so as to output the seating information to the controlling means.
Preferably, the seat adjustment amount of the seat adjusting mechanism is changed in stages, before a collision, in response to the danger level of the collision predicting information obtained from the collision danger level determining means.
Preferably, the seat adjustment amount of the seat adjusting mechanism is established, before a collision, on the basis of the seating information obtained from the occupant seating information detecting means for detecting physique and a seating state of an occupant seated in a seat.
In accordance with a fourth aspect of the present invention, there is provided a vehicle collision damage reduction system comprising at least one of object detecting means for sequentially detecting distance information to an object to be impacted moving relatively, and collision danger level determining means for determining collision danger level so as to output collision predicting information by sequentially detecting the distance information; a seatbelt pre-tensioner for a seatbelt take-up device of a seat; controlling means for outputting an operational command of webbing retraction in a predetermined amount to the seatbelt pre-tensioner on the basis of the collision predicting information obtained from the object detecting means or the collision danger level determining means; and occupant seating information detecting means for detecting physique and a seating state of an occupant seated in a seat so as to output the seating information to the controlling means.
At this time, it is preferable that the webbing take-up amount of the seatbelt pre-tensioner be changed in stages, before a collision, in response to the danger level of the collision predicting information obtained, from the collision danger level determining means.
The webbing retracting amount of the seatbelt pre-tensioner may also be more optimally established, before a collision, on the basis of the seating information obtained from the occupant seating information detecting means for detecting physique and a seating state of an occupant seated in a seat.
In accordance with a fifth aspect of the present invention, there is provided a vehicle collision damage reduction system comprising at least one object detecting means for sequentially detecting distance information to an object to be impacted moving relatively, and collision danger level determining means for determining collision danger level so as to output collision predicting information by sequentially detecting the distance information; a child seat installed to a seat in a predetermined installing state and having a reclining angle to be adjustable independently or simultaneously; controlling means for outputting an operational command of a predetermined adjustment amount of the reclining angle to the child seat on the basis of the collision predicting information obtained from the object detecting means or the collision danger level determining means; and occupant seating information detecting means for detecting the child seat installed to a seat so as to output the installing information to the controlling means.
At this time, it is preferable that the adjustment amount of the reclining angle of the child seat be changed in stages, before a collision, in response to the danger level of the collision predicting information obtained from the collision danger level determining means.
The adjustment amount of the reclining angle of the child seat may also be preferably established, before a collision, on the basis of the seating information of the child seat obtained from the occupant seating information detecting means for outputting the installing information of the child seat to the controlling means.